Film-forming apparatus

ABSTRACT

A film forming apparatus includes a spray nozzle, a first chamber, a first gas supply port, a second chamber, a through hole, and a mist outlet. A solution transformed into droplets that is to be sprayed from the spray nozzle is housed in the first chamber and transformed into a mist in the first chamber by gas injected from the first gas supply port. The solution in mist form moves from the first chamber through the through hole to the second chamber and is misted onto a substrate from the mist outlet of the second chamber.

TECHNICAL FIELD

The present invention relates to a film forming apparatus for forming afilm on a substrate.

BACKGROUND ART

Conventional techniques for forming a film on a substrate include a“spray method” and a “mist method.” The “spray method” involves sprayingdroplets of approximately 10 μm to 100 μm in diameter onto a substrate.The “mist method” involves misting droplets of approximately severalmicrometers in diameter onto a substrate.

The spray method typically uses a two-fluid spray nozzle that bombards asolution with gas to transform the solution into droplets ofapproximately several ten micrometers in diameter. On the other hand,the mist method uses, for example, an ultrasonic vibrator to transform asolution into a mist of fine droplets of approximately severalmicrometers in diameter, and conveys the solution in mist form through along pipe to a reaction chamber where a substrate is placed (or to amist outlet).

One example of prior art literature on the spray method is PatentDocument 1, and one example of prior art literature on the mist methodis Patent Document 2.

PRIOR ART LITERATURE Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No.2007-144297

Patent Literature 2: Japanese Patent Application Laid-open No.2005-307238

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The spray method, however, usually requires that a high pressure gaswith a high flow rate be used to bombard the solution. Droplets thushave a high initial velocity and directly collide with the substratethat is being heated. Since the droplets have a large diameter ofapproximately one hundred to several ten micrometers, they cannotreceive the thermal energy necessary for a chemical reaction. The spraymethod may thus result in deterioration in the quality of the film thatis formed on the substrate.

On the other hand, this problem with the spray method does not occurwith the mist method in which a solution that has been transformed intoa mist of droplets of approximately several micrometers in diameter ismisted onto a substrate. In other words, with the mist method in whichthe solution in mist form is conveyed with a stream of carrier gas andsupplied to the heated substrate, the mist has a low initial velocityand the solvent evaporates in the vicinity of the substrate surface. Themist method thus results in improvement in the quality of the film thatis formed on the substrate.

However, the mist method requires a large mechanism for transforming asolution into a mist. This increases the overall size of a film formingapparatus to which the mist method is applied.

Additionally, a film forming apparatus to which the mist method isapplied needs to convey the solution in mist form through a long pipe toa reaction chamber where the substrate is placed (or to a mist outlet).Consequently, the solution in mist form tends to coagulate in the pipe.The mist method thus may encounter difficulties in efficiently usingmaterials (solution) in the film forming process.

Moreover, this coagulation of the solution in the pipe causes the mistthat is conveyed to a substrate to have a non-uniform concentration. Itis thus necessary to provide a mechanism for rectifying the mist in themist supply unit that is in the vicinity of the substrate. A filmforming apparatus to which the mist method is applied thus also suffersfrom problems of the increased size and weight of the mist supply unitand maintenance difficulties.

In view of this, it is an object of the present invention to provide afilm forming apparatus that enables formation of a high-quality film ona substrate, effective use of a solution in the film forming process,and downsizing of the apparatus as a whole.

Means for Solving the Problems

To achieve the above-described object, the film forming apparatusaccording to the present invention is a film forming apparatus forforming a film on a substrate. It includes a spray nozzle from which asolution in droplet form is to be sprayed, a first chamber capable ofhousing the solution in droplet form that is to be sprayed from thespray nozzle, a first gas supply port from which gas is to be injectedand caused to collide with the solution housed in the first chamber, asecond chamber provided adjacent to the first chamber, a through holethat is formed in a wall surface between the first chamber and thesecond chamber and through which the solution that has collided with thegas injected from the first gas supply port and been transformed into amist is led from the first chamber into the second chamber, and a mistoutlet that is formed in the second chamber to face the substrateprovided outside the second chamber and from which the solution in mistform is misted onto the substrate.

Advantageous Effects of the Invention

The film forming apparatus according to the present invention includes aspray nozzle from which a solution in droplet form is to be sprayed, afirst chamber capable of housing the solution in droplet form that is tobe sprayed from the spray nozzle, a first gas supply port from which gasis to be injected and caused to collide with the solution housed in thefirst chamber, a second chamber provided adjacent to the first chamber,a through hole that is formed in a wall surface between the firstchamber and the second chamber and through which the solution that hascollided with the gas injected from the first gas supply port and beentransformed into a mist is led from the first chamber into the secondchamber, and a mist outlet that is formed in the second chamber to facethe substrate provided outside the second chamber and from which thesolution in mist form is misted onto the substrate.

The film forming apparatus according to the present invention is capableof transforming the solution in spray form that is sprayed from thespray nozzle into a mist inside the first chamber by bombarding thesolution with the gas ejected from the first gas supply port. Thisenables the solution in spray form to be transformed into a mist andmisted onto the substrate, without the solution coming in direct contactwith the substrate. It is thus possible to achieve film formationsimilar to CVD film formation in the atmosphere. The film formingapparatus can therefore form a high-quality film on the substrate.

Moreover, the film forming apparatus according to the present inventiontransforms a solution in spray form into a mist inside the firstchamber, which is located in the vicinity of the mist outlet from whichthe solution is misted onto the substrate. This makes the conveyancedistance of the solution in mist form considerably shorter than inconventional film forming apparatuses employing the mist method,inhibiting coagulation of the solution in mist form during conveyance.The film forming apparatus according to the present invention cantherefore effectively use the solution in the film forming process andmist the solution with a stable concentration onto a substrate.

Moreover, the film forming apparatus according to the present inventiontransforms a solution in spray form into a mist by bombarding thesprayed solution with the gas. In other words, the film formingapparatus according to the present invention has an extremely simpleconfiguration for transforming a solution into a mist and alsoeliminates the need for an ultrasonic vibrator or other elements. Thefilm forming apparatus according to the present invention can thereforeachieve downsizing of the apparatus as a whole. This simpleconfiguration also contributes to increased ease of maintenance of thefilm forming apparatus according to the present invention.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a configuration of principalpart of a film forming apparatus according to an embodiment of thepresent invention.

FIG. 2 is a plan view showing a configuration of principal part of thefilm forming apparatus according to the embodiment of the presentinvention as viewed from above.

FIG. 3 is an enlarged cross-sectional view of a configuration includinga first chamber 2 and components connected to the first chamber 2.

FIG. 4 is an enlarged cross-sectional view of a configuration includinga second chamber 4 and components connected to the second chamber 4.

FIG. 5 is an enlarged cross-sectional view of a configuration includinga third chamber 12 and components connected to the third chamber 12.

FIG. 6 is an enlarged cross-sectional view of a configuration includinga fourth chamber 8 and components connected to the fourth chamber 8.

FIG. 7 is an enlarged cross-sectional view for explaining a process ofcleaning spray nozzles 1 with a cleaning fluid.

EMBODIMENTS FOR IMPLEMENTING THE INVENTION

The present invention relates to a film forming apparatus for forming afilm on a substrate in the atmosphere. A substrate is placed in an openspace in the atmosphere, and a solution misting unit illustrated in FIG.1 is provided in an open space above the substrate. The presentinvention will now be described in detail with reference to drawingsillustrating an embodiment of the invention.

Embodiment

FIG. 1 is a cross-sectional view showing a configuration of principalpart (more specifically, in the vicinity of a solution misting unit thatmists a solution onto a substrate) of a film forming apparatus accordingto an embodiment of the present invention. FIG. 1 shows X, Y, and Zdirections. FIG. 2 is a plan view showing the configuration in FIG. 1viewed from above in FIG. 1. FIG. 2 shows the X and Y directions. Tosimplify the drawing, constituent elements 16, 17, and 60 are not shownin FIG. 2.

FIG. 3 is an enlarged cross-sectional view of a configuration includinga first chamber 2 and constituent elements 1 and 3 connected to thefirst chamber 2, which are shown in FIG. 1. FIG. 4 is an enlargedcross-sectional view of a configuration including a second chamber 4 anda constituent element 6 connected to the second chamber 4, which areshown in FIG. 1. FIG. 5 is an enlarged cross-sectional view of aconfiguration including a third chamber 12 and a constituent element 14connected to the third chamber 12, which are shown in FIG. 1. FIG. 6 isan enlarged cross-sectional view of a configuration including a fourthchamber 8 and a constituent element 7 connected to the fourth chamber 8,which are shown in FIG. 1.

The configuration of the film forming apparatus according to the presentembodiment will now be described in detail with reference to FIGS. 1 to6.

As illustrated in FIG. 1, the solution misting unit includes the fourchambers 2, 4, 8, and 12, each partitioned by wall surfaces. In otherwords, the chambers 2, 4, 8, and 12 are each surrounded by wall surfacesto form a storage space as in the configuration example in FIG. 1.

In the configuration example in FIG. 1, the first chamber 2 is adjacentto the second chamber 4 in the X direction (on the right side in FIG.1). The second chamber 4 is adjacent to the third chamber 12 in the Xdirection (on the right side in FIG. 1). That is, the first chamber 2,the second chamber 4, and the third chamber 12 are adjacent in the orderspecified in the X direction. The first chamber 2 is also adjacent tothe fourth chamber 8 in the −Z direction (on the lower side in FIG. 1).

The configuration including the first chamber 2 will first be describedwith reference to FIGS. 1, 2, and 3.

As illustrated in FIG. 2, the first chamber 2 is rectangular in planview and extends in the Y direction. The first chamber 2 is surroundedby wall surfaces to form a storage space as illustrated in FIGS. 1 and3. In other words, the wall surfaces provided on the upper, lower,right, and left sides of the first chamber 2 form a closed space in thefirst chamber 2.

As illustrated in FIGS. 1 and 3, the wall surface of the first chamber 2that is adjacent to the second chamber 4 has a through hole 5 thatconnects the first chamber 2 and the second chamber 4. There may be onlya single through hole 5, or there may be a plurality of through holes 5.The through hole 5 may have an arbitrary opening shape; one example is arectangle (slit) extending in the Y direction.

Spray nozzles 1 from which a solution in droplet form is sprayed areprovided as illustrated in FIGS. 1 and 3. Here, a solution that has beentransformed into droplets by the “spray method” is sprayed from sprayoutlets 1 a of the spray nozzles 1. In other words, droplets ofapproximately several ten micrometers in diameter are sprayed from thespray nozzles 1. The spray nozzles 1 may, for example, be two-fluidspray nozzles mentioned above. Note that the solution contains a rawmaterial of the film to be formed on a substrate 50.

In the configuration example in FIGS. 1 and 3, a switching valve 16connected to a cleaning liquid supply nozzle 17 is provided on a path ofeach spray nozzle 1. A cleaning liquid for cleaning the inside of thespray nozzle 1 is injected from a cleaning liquid supply port of thecleaning liquid supply nozzle 17.

When the switching valve 16 is switched to one position, only thecleaning liquid supply port of the cleaning liquid supply nozzle 17 isclosed, and only the solution flows into the spray nozzle 1. When theswitching valve 16 is switched to the other position, the cleaningliquid supply port of the cleaning liquid supply nozzle 17 is opened,and the fluid path of the spray nozzle 1 is closed upstream of theswitching valve 16. In this case, only the cleaning liquid injected fromthe cleaning liquid supply port of the cleaning liquid supply nozzle 17flows into the spray nozzle 1 downstream of the switching valve 16.

The upper wall surface of the first chamber 2 has a plurality of holesin which one end of the spray nozzles 1 (portion of the spray nozzles 1that is downstream of the switching valve 16) is inserted. Here, aplurality of spray nozzles 1 may be connected to the upper surface ofthe first chamber 2 as illustrated in FIG. 2 (in the configurationexample in FIG. 2, the spray nozzles 1 are aligned at a predeterminedinterval in the Y direction), or only a single spray nozzle 1 may beconnected to the upper surface of the first chamber 2. With the spraynozzles 1 connected to the first chamber 2, the holes in the uppersurface of the first chamber 2 (holes in which the spray nozzles 1 areinserted) are sealed.

The ends of the spray nozzles 1 penetrate the upper wall surface of thefirst chamber 2, and the spray outlets 1 a of the spray nozzles 1 areinside the first chamber 2.

A solution in the form of droplets of approximately several tenmicrometers in diameter is sprayed from the spray outlets 1 a of thespray nozzles 1 into the first chamber 2, and the sprayed solution ishoused in the first chamber 2.

As illustrated in FIGS. 1, 2, and 3, a plurality of first gas supplynozzles 3 are provided, and gas is injected from first gas supply ports3 a of the first gas supply nozzles 3.

The left wall surface of the first chamber 2 has a plurality of holes inwhich one end of the first gas supply nozzles 3 is inserted. Here, aplurality of first gas supply nozzles 3 may be connected to the sidesurface of the first chamber 2 as illustrated in FIG. 2 (in theconfiguration example in FIG. 2, the first gas supply nozzles 3 arearranged at a predetermined interval in the Y direction), or only asingle first gas supply nozzle 3 may be connected to the side surface ofthe first chamber 2.

The gas injected from the first gas supply ports 3 a of the first gassupply nozzles 3 collide with the solution in droplet form that ishoused in the first chamber 2. The first gas supply ports 3 a aredesirably directed toward the solution sprayed from the spray nozzles 1so that the gas injected from the first gas supply nozzles 3 collideswith the solution sprayed from the spray nozzles 1.

With the first gas supply nozzles 3 connected to the first chamber 2,the holes in the side surface of the first chamber 2 (holes in which thefirst gas supply nozzles 3 are inserted) are sealed.

The collision of the gas injected from the first gas supply nozzles 3with the solution sprayed from the spray nozzles 1 transforms thesolution in droplet form into a mist. In other words, this collisionproduces a solution in the form of a mist of droplets of approximatelyseveral micrometers in diameter in the first chamber 2.

As described above, the right side wall of the first chamber 2 has thethrough hole 5 that communicates with the second chamber 4. It is thusdesirable for the above solution in mist form to be led to the throughhole 5 with a stream of the gas injected from the first gas supplynozzles 3. In other words, it is desirable for the through hole 5 to beformed at a position that is on an extension of the injection directionin which the gas is injected from the first gas supply nozzles 3.

A heat regulator 15 capable of adjusting the temperature is provided inthe upper wall surface of the first chamber 2 as illustrated in FIGS. 1and 3. The heat regulator 15 is provided in the vicinity of the ends ofthe spray nozzles 1 and is capable of adjusting the temperature of theseends to a predetermined value.

Next, the configuration including the second chamber 4 will be describedwith reference to FIGS. 1, 2, and 4.

Like the first chamber 2, the second chamber 4 is rectangular in planview and extends in the Y direction as illustrated in FIG. 2 (in theconfiguration example in FIG. 2, the first chamber 2 and the secondchamber 4 have the same dimension in the Y direction, and their ends arealigned on both sides). As illustrated in FIGS. 1 and 4, the secondchamber 4 is surrounded by wall surfaces, except on the lower side, toform a storage space. In other words, the wall surfaces provided on theupper, right, and left sides of the second chamber 4 form a closedspace, except on the lower side, in the second chamber 4.

The lower surface of the second chamber 4 has an open mist outlet 10.The mist outlet 10 faces, at a predetermined distance, the main surfaceof the substrate 50 that is placed on a substrate placement part 60outside the second chamber 4 (see FIG. 1). Thus, the solution in mistform is misted from the mist outlet 10 onto the main surface of thesubstrate 50. The mist outlet 10 is a rectangular opening (slit)extending in the Y direction.

As described previously, the wall surface of the second chamber 4 thatis adjacent to the first chamber 2 has the through hole 5, whichconnects the first chamber 2 and the second chamber 4.

As illustrated in FIGS. 1, 2, and 4, a plurality of second gas supplynozzles 6 are provided, and gas is injected from second gas supply ports6 a of the second gas supply nozzles 6.

The upper wall surface of the second chamber 4 has a plurality of holesin which one end of the second gas supply nozzles 6 is inserted. Here, aplurality of second gas supply nozzles 6 may be connected to the uppersurface of the second chamber 4 as illustrated in FIG. 2 (in theconfiguration example in FIG. 2, the second gas supply nozzles 6 arealigned at a predetermined interval in the Y direction), or only asingle second gas supply nozzle 6 may be connected to the upper surfaceof the second chamber 4. With the second gas supply nozzles 6 connectedto the second chamber 4, the holes in the upper surface of the secondchamber 4 (holes in which the second gas supply nozzles 6 are inserted)are sealed.

The solution that has been transformed into a mist in the first chamber2 is conveyed through the through hole 5 into the second chamber 4 andhoused in the second chamber 4. The gas injected from the second gassupply ports 6 a leads the solution in mist form that is housed in thesecond chamber 2 toward the mist outlet 10.

Next, the configuration including the third chamber 12 will be describedwith reference to FIGS. 1, 2, and 5.

Like the first chamber 2 and the second chamber 4, the third chamber 12is rectangular in plan view and extends in the Y direction asillustrated in FIG. 2 (in the configuration example in FIG. 2, the firstchamber 2, the second chamber 4, and the third chamber 12 have the samedimension in the Y direction, and their ends are aligned on both sides).As illustrated in FIGS. 1 and 5, the third chamber 12 is surrounded bywall surfaces, except on the lower side, to form a storage space. Inother words, the wall surfaces provided on the upper, right, and leftsides of the third chamber 12 form a closed space, except on the lowerside, in the third chamber 12.

The lower surface of the third chamber 12 has an open exhaust port 11.The exhaust port 11 faces, at a predetermined distance, the main surfaceof the substrate 50 that is placed on the substrate placement part 60outside the third chamber 12 (see FIG. 1). Unreacted liquids or gasremaining above the substrate 50 are sucked through the exhaust port 11.The exhaust port 11 is a rectangular opening (slit) extending in the Ydirection. As illustrated in FIG. 1, the exhaust port 11 is adjacent tothe right side of the mist outlet 10, and the mist outlet 10 and theexhaust port 11 are at the same height.

As illustrated in FIGS. 1, 2, and 5, a plurality of exhaust nozzles 14are provided, and suction is exerted through exhaust holes 14 a of theexhaust nozzles 14.

The upper wall surface of the third chamber 12 has a plurality of holesin which one end of the exhaust nozzles 14 is inserted. Here, aplurality of exhaust nozzles 14 may be connected to the upper surface ofthe third chamber 12 as illustrated in FIG. 2 (in the configurationexample in FIG. 2, the exhaust nozzles 14 are aligned at a predeterminedinterval in the Y direction), or only a single exhaust nozzle 14 may beconnected to the upper surface of the third chamber 12. With the exhaustnozzles 14 connected to the third chamber 12, the holes in the uppersurface of the third chamber 12 (holes in which the exhaust nozzles 14are inserted) are sealed.

Note that the third chamber 12 has formed therein a partition plate 13that extends diagonally upward as illustrated in FIGS. 1 and 5. One endof the partition plate 13 is connected to one side surface of the thirdchamber 12, but the other end of the partition plate 13 is not connectedto the other side surface of the third chamber 12.

By the suction exerted through the exhaust nozzles 14, gas and liquidsremaining above the substrate 50 are drawn up through the exhaust port11. The presence of the partition plate 13 inhibits gas and liquids thatare sucked through the exhaust port 11 above the partition plate 13 inthe third chamber 12 from dropping back toward the exhaust port 11.

Next, the configuration including the fourth chamber 8 will be describedwith reference to FIGS. 1, 2, and 6.

The fourth chamber 8 is provided on the underside of the first chamber2, and like the first chamber 2, is rectangular in plan view and extendsin the Y direction (the first chamber 2 and the fourth chamber 8 havethe same dimension in the Y direction, and their ends are aligned onboth sides). As illustrated in FIGS. 1 and 6, the fourth chamber 8 issurrounded by wall surfaces to form a storage space. In other words, thewall surfaces provided on the upper, lower, right, and left sides of thefourth chamber 8 form a closed space in the fourth chamber 8.

The lower wall surface of the fourth chamber 8 has a third gas supplyport 9. The third gas supply port 9 faces, at a predetermined distance,the main surface of the substrate 50 that is placed on the substrateplacement part 60 outside the fourth chamber 8 (see FIG. 1). Gas isejected from the third gas supply port 9 toward the upper surface of thesubstrate 50. The third gas supply port 9 is a rectangular opening(slit) extending in the Y direction. As illustrated in FIG. 1, the thirdgas supply port 9 is adjacent to the left side of the mist outlet 10,and the mist outlet 10 and the third gas supply port 9 are at the sameheight.

As illustrated in FIGS. 1, 2, and 6, a plurality of third gas supplynozzles 7 are provided, and gas is ejected from exhaust ports 7 a of thethird gas supply nozzles 9 into the fourth chamber 8.

A side wall surface of the fourth chamber 8 has a plurality of holes inwhich one end of the third gas supply nozzles 7 is inserted. Here, aplurality of third gas supply nozzles 7 may be connected to the sidesurface of the fourth chamber 8 as illustrated in FIG. 2 (in theconfiguration example in FIG. 2, the third gas supply nozzles 7 arearranged at a predetermined interval in the Y direction), or only asingle third gas supply nozzle 7 may be connected to the side surface ofthe fourth chamber 8. With the third gas supply nozzles 7 connected tothe fourth chamber 8, the holes in the side surface of the fourthchamber 8 (holes in which the third gas supply nozzles 7 are inserted)are sealed.

The gas injected from the third gas supply nozzles 7 is housed in thefourth chamber 8 and then injected to the upper surface of the substrate50 from the third gas supply port 9 of the fourth chamber 8.

Note that the film forming apparatus is provided with the substrateplacement part 60 on which the substrate 50 is placed as illustrated inFIG. 1. The substrate placement part 60 on which the substrate 50 isplaced moves in the left and right directions (X direction) (anyhorizontal movement is possible). Specifically, this movement of thesubstrate placement part 60 causes the substrate 50 to move in thehorizontal direction while the solution in mist form is misted in thevertical direction from the mist outlet 10 onto the substrate 50. Also,the substrate placement part 60 includes a heater that heats thesubstrate 50 placed on the substrate placement part 60 to apredetermined temperature (temperature for film formation).

Next, the film forming process will be described.

The substrate 50 is placed on the substrate placement part 60. Thesubstrate placement part 60 is then moved in the X direction until thesubstrate 50 moves to a position under the mist outlet 10. Here, theheater of the substrate placement part 60 heats the substrate 50 to thetemperature for film formation.

Meanwhile, a solution in spray form (solution in droplet form) issprayed from the spray nozzles 1 into the first chamber 2. Here, theswitching valve 16 has been switched to one position in which thecleaning liquid supply port of the cleaning liquid supply nozzle 17 isclosed. Thus, only the solution flows through the liquid path of thespray nozzle 1. Also, the gas is ejected from the first gas supply ports3 a toward the solution in spray form that is housed in the firstchamber 2.

The resultant collision of the gas ejected from the first gas supplyports 3 a with the solution in spray form produces a solution in mistform in the first chamber 2. In other words, this collision furtherreduces the particle diameter of the solution in spray form andaccordingly atomizes the solution.

The solution in mist form is led through the through hole 5 into thesecond chamber 4 with a stream of the gas ejected from the first gassupply ports 3 a. In the second chamber 4, the solution in mist form isled toward the ejection outlet 10 with a stream of the gas ejected fromthe second gas supply ports 6 a. The solution in mist form is thenmisted from the mist outlet 10 onto the upper surface of the substrate50.

Here, the suction exerted through the exhaust port 11 produces a flowfrom the mist outlet 10 toward the exhaust port 11. That is, a flow inwhich the solution in mist form misted from the mist outlet 10 movestoward the exhaust port 11 is produced on the upper surface side of thesubstrate 50. Gas and liquids sucked through the exhaust port 11 areexhausted to the outside via the third chamber 12 and the exhaustnozzles 14.

When the solution in mist form is misted from the mist outlet 10, gas isejected from the third gas supply port 9 toward the upper surface of thesubstrate 50. As described previously, the gas ejected from the thirdgas supply port 9 has been supplied from the third gas supply nozzles 7into the fourth chamber 8. The ejection of the gas from the third gassupply port 9 prevents the solution misted from the mist outlet 10 fromleaking to the left side of the third gas supply port 9. In other words,the gas ejected from the third gas supply port 9 functions as a “screen”against the solution misted from the mist outlet 10.

The suction exerted through the exhaust port 11 also produces a flowfrom the third gas supply port 9 to the exhaust port 11. That is, a flowin which the gas injected from the third gas supply port 9 moves towardthe exhaust port 11 is produced on the upper surface side of thesubstrate 50.

Simultaneously with the misting of the solution from the mist outlet 10,the suction exerted through the exhaust port 11, and the ejection of thegas from the third gas supply port 9 described above, the substrateplacement part 60 is moved in the X direction. Accordingly, the solutionmisted from the mist outlet 10 reacts with the air and forms a uniformfilm over the entire upper surface of the heated substrate 50.

Here, the solution sprayed from the spray nozzles 1 can be arbitrarilyselected according to the film to be formed. The gas to be ejected fromthe nozzles 3, 6, and 7 can also be selected arbitrarily.

For example, in the case where a solution that has high reactivity withoxygen is sprayed from the spray nozzles 1, it is desirable to inject aninert gas from the first gas supply ports 3 a and the second gas supplyports 6 a and to inject an oxidizing agent (e.g., a fluid containingwater, oxygen, or ozone) from the third gas supply port 9. This inhibitsoxidation of the solution inside the first chamber 2 and the secondchamber 4 and accelerates the reaction of the misted solution and theoxidizing agent in the space between the mist outlet 10 and thesubstrate 50.

In the case where a solution that has high reactivity with oxygen issprayed from the spray nozzles 1, it is also possible to inject an inertgas from the first gas supply ports 3 a and to inject an oxidizing agent(e.g., oxygen or ozone) from the second gas supply ports 6 a. In thiscase, for example, air may be injected from the third gas supply port 9.This inhibits oxidation of the solution inside the first chamber 2 andaccelerates the reaction of the solution in mist form and the oxidizingagent, thus enabling the solution that is oxidizing to be misted towardthe substrate 50.

As described above, the film forming apparatus according to the presentembodiment includes the first chamber 2 capable of housing a solution indroplet form that is sprayed from the spray nozzles 1. The film formingapparatus also includes the first gas supply ports 3 a from which thegas is to be injected and caused to collide with the solution housed inthe first chamber 2, and the second chamber 4 adjacent to the firstchamber 2. The wall surface between the first chamber 2 and the secondchamber 4 has the through hole 5 through which the solution in mist formflows. The film forming apparatus also includes the mist outlet 10,which is formed in the second chamber 4 to face the substrate 50 placedoutside the second chamber 4 and from which the solution in mist form ismisted onto the substrate 50.

The film forming apparatus thus enables the solution in droplet form,which is sprayed from the spray nozzles 1, to be transformed into a mistinside the first chamber 2 by bombarding the solution with the gasejected from the first gas supply ports 3 a. This enables the solutionin spray form to be transformed into a mist and misted onto thesubstrate 50, without the solution coming in direct contact with thesubstrate 50. It is thus possible to achieve film formation similar toCVD film formation in the atmosphere. The film forming apparatus cantherefore form a high-quality film on the substrate 50.

Moreover, the film forming apparatus transforms a solution in spray forminto a mist inside the first chamber 2, which is located in the vicinityof the mist outlet 10 from which the solution is misted onto thesubstrate 50. This makes the conveyance distance of the solution in mistform considerably shorter than in conventional film forming apparatusesemploying the mist method, inhibiting coagulation of the solution inmist form during conveyance. The film forming apparatus according to thepresent invention can therefore effectively use the solution in the filmforming process and mist the solution with a stable concentration ontothe substrate 50.

Moreover, the film forming apparatus according to the present inventiontransforms a solution in spray form into a mist by bombarding thesprayed solution with the gas. In other words, the film formingapparatus according to the present invention has an extremely simpleconfiguration for transforming a solution into a mist and alsoeliminates the need for an ultrasonic vibrator or other elements. Thefilm forming apparatus according to the present invention can thereforeachieve downsizing of the apparatus as a whole. This simpleconfiguration also contributes to increased ease of maintenance of thefilm forming apparatus according to the present invention.

Therefore, the film forming apparatus according to the present inventioncan have the benefits of both the mist method and the spray method,i.e., the improved film quality achieved by the mist method and thesimple configuration and increased ease of maintenance achieved by thespray method.

Additionally, the first chamber 2 can prevent the solution in largedroplet form sprayed from the spray nozzle 1 from scattering around thechamber. The second chamber 4 can also prevent the solution in mist formfrom scattering around the chamber. The fourth chamber 8 can alsoprevent the gas from scattering around the chamber. The third chamber 12enables processing for collectively discharging liquids and gas.

The film forming apparatus according to the present invention furtherincludes the second gas supply ports 6 a from which the gas is injectedto lead the solution in mist form that is housed in the second chamber 4toward the mist outlet 10. This produces a flow of supply of thesolution in mist form to the substrate 50.

The film forming apparatus according to the present invention furtherincludes the exhaust port 11 adjacent to the mist outlet 10. Thisproduces a flow from the mist outlet 10 to the exhaust port 11. That is,a flow in which the solution in mist form misted from the mist outlet 10moves toward the exhaust port 11 is produced on the upper surface sideof the substrate 50.

The film forming apparatus according to the present invention furtherincludes the third gas supply port 9 that is provided adjacent to themist outlet 10 and from which the gas is injected. This prevents thesolution misted from the mist outlet 10 from leaking to the left side ofthe third gas supply port 9.

Here, the mist outlet 10, the exhaust port 11, and the third gas supplyport 9 are each in the shape of a slit extending in the Y direction. Itis thus possible to uniformly mist the solution in mist form that ishoused in the second chamber 4 from the mist outlet 10, uniformly injectthe gas housed in the fourth chamber 8 from the third gas supply port 9,and uniformly exhaust the gas in the Y direction from the exhaust port11.

In the film forming apparatus according to the present invention, thespray nozzles 1 are provided through the upper wall surface of the firstchamber 2. This wall surface through which the spray nozzles 1 areprovided includes the heat regulator 15.

It is thus possible to keep the vicinity of the spray outlets 1 a of thespray nozzles 1 at a predetermined temperature. This preventscoagulation of the solution in the vicinity of the spray outlets 1 a ofthe spray nozzles 1, thus preventing clogging of the spray nozzles 1.

The film forming apparatus according to the present invention furtherincludes the substrate placement part 60 that moves in the horizontaldirection. It is thus possible to form a film on the large-areasubstrate 50 without moving the constituent elements of the solutionmisting unit. Note that the substrate placement part 60 including theheater can also heat the substrate 50 placed thereon.

Note that the film forming apparatus according to the present embodimentcan also employ the following configuration.

Specifically, the film forming apparatus may include a moving mechanismfor moving a unit consisting of the spray nozzles 1, the switchingvalves 16, and the cleaning liquid supply nozzles 17 in the vertical andhorizontal directions. In this case, the film forming apparatus performsthe following processing when cleaning the spray nozzles 1.

The aforementioned unit is first moved in the up direction in FIG. 1 bythe aforementioned moving mechanism to pull the ends of the spraynozzles 1 out of the upper wall surface of the first chamber. The unitis then moved in, for example, the horizontal direction by the movingmechanism. The ends of the spray nozzles 1 are accordingly located abovea container 30, which is provided outside the area for the film formingprocess, as illustrated in FIG. 7.

Then, the switching valves 16 are switched to one position in which thecleaning liquid supply ports of the cleaning liquid supply nozzles 17are opened, and the fluid paths of the spray nozzles 1 are closedupstream of the switching valves 16. This creates a situation in whichthe cleaning liquid supply ports, from which the cleaning liquid issupplied, are connected to the fluid paths of the spray nozzles 1.

Then, the cleaning liquid flowing from the cleaning liquid supplynozzles 17 flows through the fluid paths of the spray nozzles 1 to cleancontamination caused by the solution flowing through the fluid paths ofthe spray nozzles 1. Note that the cleaning liquid output from the sprayoutlets 1 a of the spray nozzles 1 is housed in the container 30.

In the case of performing the film forming process after the cleaning ofthe spray nozzles 1, the unit is moved by the moving mechanism so thatthe spray nozzles 1 are inserted into the holes in the upper surface ofthe first chamber 2 as illustrated in FIG. 1. Then, the switching valves16 are switched to the other position in which only the cleaning liquidsupply ports of the cleaning liquid supply nozzles 17 are closed, andonly the solution flows through the fluid paths of the spray nozzles 1.

The above-described moving and cleaning mechanisms enable appropriatecleaning of the spray nozzles 1 that are contaminated by the filmforming process.

In the present invention, the solution misting unit illustrated in FIG.1 is provided in an open space in the atmosphere, and the space betweenthe solution misting unit and the substrate 50 is not closed due tohorizontal movement of the substrate placement part 60. In the presentinvention, the presence of the exhaust port 11 produces a constant fluidflow in the space (i.e., open space) between the solution misting unitand the substrate 50.

The film forming apparatus according to the present invention cantherefore prevent adhesion of particles such as products in the spacebetween the solution misting unit and the substrate 50. Accordingly, thefilm forming apparatus can also prevent deterioration in the quality ofthe formed film due to the mixing of particles to the film.

The open space between the solution misting unit and the substrate 50also increases the ease of maintenance of the portion of the solutionmisting unit that faces the substrate 50. In addition, the gas isinjected from the second gas supply ports 6 a to lead the solution inmist form from the second chamber 4 to the mist outlet 10 (i.e., thesubstrate 50). This makes it possible to increase the distance betweenthe solution misting unit and the substrate 50, thus enhancing theabove-described effect.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore to be understood that numerousmodifications and variations can be devised without departing from thescope of the invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 Spray nozzle    -   la Spray outlet    -   2 First chamber    -   3 First gas supply nozzle    -   3 a First gas supply port    -   4 Second chamber    -   5 Through hole    -   6 Second gas supply nozzle    -   6 a Second gas supply port    -   7 Third gas supply nozzle    -   8 Fourth chamber    -   9 Third gas supply port    -   10 Mist outlet    -   11 Exhaust port    -   12 Third chamber    -   13 Partition plate    -   14 Exhaust nozzle    -   15 Heat regulator    -   16 Switching valve    -   17 Cleaning liquid supply nozzle    -   30 Container    -   50 Substrate    -   60 Substrate placement part

1. A film forming apparatus for forming a film on a substrate,comprising: a spray nozzle from which a solution in droplet form is tobe sprayed; a first chamber capable of housing said solution in dropletform that is to be sprayed from said spray nozzle; a first gas supplyport from which gas is to be injected and caused to collide with saidsolution housed in said first chamber; a second chamber providedadjacent to said first chamber; a through hole that is formed in a wallsurface between said first chamber and said second chamber and throughwhich said solution that has collided with said gas injected from saidfirst gas supply port and been transformed into a mist is led from saidfirst chamber into said second chamber; and a mist outlet that is formedin said second chamber to face said substrate provided outside saidsecond chamber and from which said solution in mist form is misted ontosaid substrate.
 2. The film forming apparatus according to claim 1,further comprising: a second gas supply port from which gas is to beinjected to lead said solution in mist form that is housed in saidsecond chamber to said mist outlet.
 3. The film forming apparatusaccording to claim 2, further comprising: an exhaust port that is formedfacing said substrate and adjacent to one side of said mist outlet andthrough which a fluid is to be exhausted.
 4. The film forming apparatusaccording to claim 3, further comprising: a third gas supply port thatis formed facing said substrate and adjacent to another side of saidmist outlet and from which gas is to be injected.
 5. The film formingapparatus according to claim 1, wherein said mist outlet is arectangular opening.
 6. The film forming apparatus according to claim 3,wherein said exhaust port is a rectangular opening.
 7. The film formingapparatus according to claim 4, wherein said third gas supply port is arectangular opening.
 8. The film forming apparatus according to claim 1,wherein said spray nozzle is provided through a wall surface of saidfirst chamber, and said wall surface through which said spray nozzle isprovided includes a heat regulator that is capable of adjusting atemperature.
 9. The film forming apparatus according to claim 1, whereinsaid spray nozzle is movable, and said spray nozzle includes a cleaningliquid supply port from which a cleaning liquid is supplied to a fluidpath of said spray nozzle.
 10. The film forming apparatus according toclaim 1, further comprising: a substrate placement unit on which saidsubstrate is to be placed and that moves in a horizontal directionrelative to said mist outlet.
 11. The film forming apparatus accordingto claim 10, wherein said substrate placement unit includes a heater.12. The film forming apparatus according to claim 4, wherein saidsolution that reacts with oxygen is sprayed from said spray nozzle, aninert gas is injected from said first gas supply port, an inert gas isinjected from said second gas supply port, and an oxidizing agent isinjected from said third gas supply port.
 13. The film forming apparatusaccording to claim 2, wherein said solution that reacts with oxygen issprayed from said spray nozzle, an inert gas is injected from said firstgas supply port, and an oxidizing agent is injected from said second gassupply port.